Characteristics and treatment of acute myeloid neoplasms with cutaneous involvement in infants up to 6 months of age: A retrospective study.

BACKGROUND: Myeloid neoplasms account for 50% of cases of pediatric leukemias in infants. Approximately 25%-50% of patients with newborn leukemia have cutaneous extramedullary disease (EMD). In less than 10% of patients, aleukemic leukemia cutis or isolated extramedullary disease with cutaneous involvement (cEMD) occurs when skin lesions appear prior to bone marrow involvement and systemic symptoms. Interestingly, in acute myeloid leukemia with cutaneous EMD (AML-cEMD) and cEMD, spontaneous remissions have been reported. METHOD: This is a multicentric retrospective cohort study aiming to describe characteristics, treatment, and outcome of infants with either cEMD or presence of cutaneous disease with involvement of the bone marrow (AML-cEMD). This study included patients born between 1990 and 2018 from Italy, the Netherlands, Switzerland, and the United States, diagnosed between 0 and 6 months of life with cEMD or AML-cEMD. Descriptive statistics, Fisher's exact test, Kaplan-Meier method, and log rank test were applied. RESULTS: The cohort consisted of n = 50 patients, including 42 AML-cEMD and eight cEMD patients. The most common genetic mutation found was a KMT2A rearrangement (n = 26, 52%). Overall 5-year event-free survival (EFS) and overall survival (OS) were 66% [confidence interval (CI): 51-78] and 75% [CI: 60-85], respectively. In two patients, complete spontaneous remission occurred without any therapy. Central nervous system (CNS) involvement was found in 25% of cEMD patients. No difference in outcomes was observed between the AML-cEMD and cEMD groups, but none of the latter patients included in the study died. KMT2A rearrangements were not associated with poorer prognosis. CONCLUSION: In the largest cohort to date, our study describes the characteristics of infants with cutaneous involvement of myeloid neoplasms including cytomolecular findings and survival rates. Further prospective biologic and clinical studies of these infants with myeloid neoplasms will be required to individualize therapy for this rare patient population.

Optimized Cytogenetic Risk-Group Stratification of KMT2A-Rearranged Pediatric Acute Myeloid Leukemia.

Comprehensive international consensus on cytogenetic risk-group stratification of KMT2A-rearranged (KMT2A-r) pediatric acute myeloid leukemia (AML) is lacking. This retrospective (2005-2016) International Berlin-Frankfurt-Münster Study Group study on 1,256 children with KMT2A-r AML aimed to validate the prognostic value of established recurring KMT2A fusions and additional cytogenetic aberrations (ACAs), and secondly, to define additional, recurring KMT2A fusions and ACAs, evaluating their prognostic relevance. Compared to our previous study, three additional, recurring KMT2A-r groups were defined: Xq24/KMT2A::SEPT6, 1p32/KMT2A::EPS15, 17q12/t(11;17)(q23;q12). Across 13 KMT2A-r groups, 5-year event-free survival probabilities varied significantly (21.8% to 76.2%; P<0.01). ACAs occurred in 46.8% of 1,200 patients with complete karyotypes, correlating with inferior overall survival (56.8% vs 67.9%; P<0.01). Multivariable analyses confirmed independent associations of 4q21/KMT2A::AFF1, 6q27/KMT2A::AFDN, 10p12/KMT2A::MLLT10, 10p11.2/KMT2A::ABI1, and 19p13.3/KMT2A::MLLT1 with adverse outcomes, but not those of 1q21/KMT2A::MLLT11 and trisomy 19 with favorable and adverse outcomes, respectively. Newly identified ACAs with independent adverse prognoses were monosomy 10, trisomies 1, 6, 16, and X, add(12p), and del(9q). Among patients with 9p22/KMT2A::MLLT3, the independent association of French-American-British-type M5 with favorable outcome was confirmed, and those of trisomy 6 and measurable residual disease at end of induction with adverse outcomes were identified. We provide evidence to incorporate the five adverse-risk KMT2A fusions into the cytogenetic risk-group stratification of KMT2A-r pediatric AML, to revise the favorable-risk classification of 1q21/KMT2A::MLLT11 to intermediate risk, and to refine risk-stratification of 9p22/KMT2A::MLLT3 AML. Future studies should validate the associations between the newly identified ACAs and outcome, and unravel the underlying biological pathogenesis of KMT2A fusions and ACAs.

Treatment outcomes of childhood PICALM::MLLT10 acute leukaemias.

The prognostic impact of PICALM::MLLT10 status in childhood leukaemia is not well described. Ten International Berlin Frankfurt Münster-affiliated study groups and the Children's Oncology Group collaborated in this multicentre retrospective study. The presence of the PICALM::MLLT10 fusion gene was confirmed by fluorescence in situ hybridization and/or RNA sequencing at participating sites. Ninety-eight children met the study criteria. T-cell acute lymphoblastic leukaemia (T-ALL) and acute myeloid leukaemia (AML) predominated 55 (56%) and 39 (40%) patients, respectively. Most patients received a chemotherapy regimen per their disease phenotype: 58% received an ALL regimen, 40% an AML regimen and 1% a hybrid regimen. Outcomes for children with PICALM::MLLT10 ALL were reasonable: 5-year event-free survival (EFS) 67% and 5-year overall survival (OS) 76%, but children with PICALM::MLLT10 AML had poor outcomes: 5-year EFS 22% and 5-year OS 26%. Haematopoietic stem cell transplant (HSCT) did not result in a significant improvement in outcomes for PICALM::MLLT10 AML: 5-year EFS 20% for those who received HSCT versus 23% for those who did not (p = 0.6) and 5-year OS 37% versus 36% (p = 0.7). In summary, this study confirms that PICALM::MLLT10 AML is associated with a dismal prognosis and patients cannot be salvaged with HSCT; exploration of novel therapeutic options is warranted.

Treating CD33-Positive de novo Acute Myeloid Leukemia in Pediatric Patients: Focus on the Clinical Value of Gemtuzumab Ozogamicin.

Although survival in pediatric acute myeloid leukemia (AML) has increased considerably over the past decades, refractory disease and relapse rates remain high. Refractory and relapsed disease are difficult to treat, with overall survival rates less than 40-50%. Preventing relapse should, therefore, be one of the highest priorities. Current conventional chemotherapy regimens are hard to intensify due to associated toxic complications, hence more effective therapies that do not increase toxicity are needed. A promising targeted agent is the CD33-directed antibody-drug conjugate gemtuzumab ozogamicin (GO). Because CD33 is highly expressed on leukemic cells in the majority of AML patients, GO can be useful for a broad range of patients. Better relapse-free survival (RFS) after therapy including GO has been reported in several pediatric clinical trials; however, ambiguity about the clinical value of GO in newly diagnosed children remains. Treatment with GO in de novo AML patients aged ≥1 month, in combination with standard chemotherapy is approved in the United States, whereas in Europe, GO is only approved for newly diagnosed patients aged ≥15 years. In this review, we aimed to clarify the clinical value of GO for treatment of newly diagnosed pediatric AML patients. Based on current literature, GO seems to have additional value, in terms of RFS, and acceptable toxicity when used in addition to chemotherapy during initial treatment. Moreover, in KMT2A-rearranged patients, the clinical value of GO was even more evident. Also, we addressed predictors of response, being CD33 expression and SNPs, PgP-1 and Annexin A5. The near finalized intent-to-file clinical trial in the MyeChild consortium investigates whether fractionated dosing has additional value for pediatric AML, which may pave the way for a broader application of GO in pediatric AML.

Measurable Residual Disease and Fusion Partner Independently Predict Survival and Relapse Risk in Childhood KMT2A-Rearranged Acute Myeloid Leukemia: A Study by the International Berlin-Frankfurt-Münster Study Group.

PURPOSE: A previous study by the International Berlin-Frankfurt-Münster Study Group (I-BFM-SG) on childhood KMT2A-rearranged (KMT2A-r) AML demonstrated the prognostic value of the fusion partner. This I-BFM-SG study investigated the value of flow cytometry-based measurable residual disease (flow-MRD) and evaluated the benefit of allogeneic stem-cell transplantation (allo-SCT) in first complete remission (CR1) in this disease. METHODS: A total of 1,130 children with KMT2A-r AML, diagnosed between January 2005 and December 2016, were assigned to high-risk (n = 402; 35.6%) or non-high-risk (n = 728; 64.4%) fusion partner-based groups. Flow-MRD levels at both end of induction 1 (EOI1) and 2 (EOI2) were available for 456 patients and were considered negative (<0.1%) or positive (≥0.1%). End points were 5-year event-free survival (EFS), cumulative incidence of relapse (CIR), and overall survival (OS). RESULTS: The high-risk group had inferior EFS (30.3% high risk v 54.0% non-high risk; P < .0001), CIR (59.7% v 35.2%; P < .0001), and OS (49.2% v 70.5%; P < .0001). EOI2 MRD negativity was associated with superior EFS (n = 413; 47.6% MRD negativity v n = 43; 16.3% MRD positivity; P < .0001) and OS (n = 413; 66.0% v n = 43; 27.9%; P < .0001), and showed a trend toward lower CIR (n = 392; 46.1% v n = 26; 65.4%; P = .016). Similar results were obtained for patients with EOI2 MRD negativity within both risk groups, except that within the non-high-risk group, CIR was comparable with that of patients with EOI2 MRD positivity. Allo-SCT in CR1 only reduced CIR (hazard ratio, 0.5 [95% CI, 0.4 to 0.8]; P = .00096) within the high-risk group but did not improve OS. In multivariable analyses, EOI2 MRD positivity and high-risk group were independently associated with inferior EFS, CIR, and OS. CONCLUSION: EOI2 flow-MRD is an independent prognostic factor and should be included as risk stratification factor in childhood KMT2A-r AML. Treatment approaches other than allo-SCT in CR1 are needed to improve prognosis.

Comprehensive molecular and clinical characterization of NUP98 fusions in pediatric acute myeloid leukemia.

NUP98 fusions comprise a family of rare recurrent alterations in AML, associated with adverse outcomes. In order to define the underlying biology and clinical implications of this family of fusions, we performed comprehensive transcriptome, epigenome, and immunophenotypic profiling of 2,235 children and young adults with AML and identified 160 NUP98 rearrangements (7.2%), including 108 NUP98-NSD1 (4.8%), 32 NUP98-KDM5A (1.4%) and 20 NUP98-X cases (0.9%) with 13 different fusion partners. Fusion partners defined disease characteristics and biology; patients with NUP98-NSD1 or NUP98-KDM5A had distinct immunophenotypic, transcriptomic, and epigenomic profiles. Unlike the two most prevalent NUP98 fusions, NUP98-X variants are typically not cryptic. Furthermore, NUP98-X cases are associated with WT1 mutations, and have epigenomic profiles that resemble either NUP98-NSD1 or NUP98-KDM5A. Cooperating FLT3-ITD and WT1 mutations define NUP98-NSD1, and chromosome 13 aberrations are highly enriched in NUP98-KDM5A. Importantly, we demonstrate that NUP98 fusions portend dismal overall survival, with the noteworthy exception of patients bearing abnormal chromosome 13 (clinicaltrials gov. Identifiers: NCT00002798, NCT00070174, NCT00372593, NCT01371981).

Outcome of chimeric antigen receptor T-cell therapy following treatment with inotuzumab ozogamicin in children with relapsed or refractory acute lymphoblastic leukemia.

Chimeric antigen receptor T cells targeting CD19 (CART-19) have shown remarkable efficacy for relapsed/refractory (R/R) B-cell precursor acute lymphoblastic leukemia (BCP-ALL). We investigated whether prior use of inotuzumab ozogamicin (InO), an anti-CD22 antibody conjugated to calicheamicin, may impact CAR T-cell manufacturing or efficacy via pre-CART-19 depletion of the B-cell compartment. In this international, retrospective analysis, 39 children and young adults receiving InO before (n = 12) and/or after (n = 27) T-cell apheresis as bridging therapy to CART-19 treatment were analyzed. Median age at infusion was 13 years (range 1.4-23 years). Thirty-four out of 39 patients (87.2%) obtained complete remission. With a median follow-up of 18.2 months after CART-19 infusion, 12-month event-free survival (EFS) was 53.3% (95% confidence interval (CI): 38.7-73.4) and overall survival (OS) was 77.8% (95% CI: 64.5-93.9). Seventeen patients (44%) relapsed with a median of 159 days (range 28-655) after CART-19 infusion. No difference in day 28 minimal residual disease negative complete response rate, 12-month OS/EFS, or incidence of CD19-positive or -negative relapses was observed among patients receiving InO before or after apheresis. Compared to published data for patients treated with CART-19 therapy without prior InO exposure, response and OS/EFS for patients treated with InO prior to CART-19 are similar.

Effect of Antibacterial Prophylaxis on Febrile Neutropenic Episodes and Bacterial Bloodstream Infections in Dutch Pediatric Patients with Acute Myeloid Leukemia: A Two-Center Retrospective Study.

Bloodstream infections (BSIs), especially those caused by Gram-negative rods (GNR) and viridans group streptococci (VGS), are common and potentially life-threatening complications of pediatric acute myeloid leukemia (AML) treatment. Limited literature is available on prophylactic regimens. We retrospectively evaluated the effect of different antibacterial prophylaxis regimens on the incidence of febrile neutropenic (FN) episodes and bacterial BSIs. Medical records of children (0−18 years) diagnosed with de novo AML and treated at two Dutch centers from May 1998 to March 2021 were studied. Data were analyzed per chemotherapy course and consecutive neutropenic period. A total of 82 patients had 316 evaluable courses: 92 were given with single-agent ciprofloxacin, 138 with penicillin plus ciprofloxacin, and 51 with teicoplanin plus ciprofloxacin. The remaining 35 courses with various other prophylaxis regimens were not statistically compared. During courses with teicoplanin plus ciprofloxacin, significantly fewer FN episodes (43 vs. 90% and 75%; p < 0.0001) and bacterial BSIs (4 vs. 63% and 33%; p < 0.0001) occurred than with single-agent ciprofloxacin and penicillin plus ciprofloxacin, respectively. GNR and VGS BSIs did not occur with teicoplanin plus ciprofloxacin and no bacterial BSI-related pediatric intensive care unit (PICU) admissions were required, whereas, with single-agent ciprofloxacin and penicillin plus ciprofloxacin, GNR BSIs occurred in 8 and 1% (p = 0.004), VGS BSIs in 24 and 14% (p = 0.0005), and BSI-related PICU admissions were required in 8 and 2% of the courses (p = 0.029), respectively. Teicoplanin plus ciprofloxacin as antibacterial prophylaxis is associated with a lower incidence of FN episodes and bacterial BSIs. This may be a good prophylactic regimen for pediatric AML patients during treatment.

Elevated Mutational Age in Blood of Children Treated for Cancer Contributes to Therapy-Related Myeloid Neoplasms.

Childhood cancer survivors are confronted with various chronic health conditions like therapy-related malignancies. However, it is unclear how exposure to chemotherapy contributes to the mutation burden and clonal composition of healthy tissues early in life. Here, we studied mutation accumulation in hematopoietic stem and progenitor cells (HSPC) before and after cancer treatment of 24 children. Of these children, 19 developed therapy-related myeloid neoplasms (t-MN). Posttreatment HSPCs had an average mutation burden increase comparable to what treatment-naïve cells accumulate during 16 years of life, with excesses up to 80 years. In most children, these additional mutations were induced by clock-like processes, which are also active during healthy aging. Other patients harbored mutations that could be directly attributed to treatments like platinum-based drugs and thiopurines. Using phylogenetic inference, we demonstrate that most t-MN in children originate after the start of treatment and that leukemic clones become dominant during or directly after chemotherapy exposure. SIGNIFICANCE: Our study shows that chemotherapy increases the mutation burden of normal blood cells in cancer survivors. Only few drugs damage the DNA directly, whereas in most patients, chemotherapy-induced mutations are caused by processes similar to those present during normal aging. This article is highlighted in the In This Issue feature, p. 1825.

Mucormycosis in Children With Hematologic Malignancies: A Case Series and Review of the Literature.

BACKGROUND: Mucormycosis is classified as the third leading cause of invasive fungal disease in immunocompromised patients and is characterized by high morbidity and mortality (33%-56%). The aim of this study is to describe presentation, treatment and outcome of Dutch pediatric hemato-oncology patients recently diagnosed with mucormycosis and to review the literature to gain more insight specifically into contemporary outcome data. METHODS: Ten cases were diagnosed in the Princess Máxima Center for Pediatric Oncology from 2018 to 2021 and were retrospectively reviewed. In addition, 9 case series (n = 148) were included from literature. RESULTS: In our case series, 5 patients of 10 children (age 2-17 years) had disseminated invasive fungal disease. Four patients had localized pulmonary disease and 1 had a localized renal infection. One diagnosis was made postmortem. The underlying diseases were acute lymphoblastic leukemia (n = 6), acute myeloid leukemia (n = 2) and lymphoma (n=2). Seven patients received combination therapy comprising of a lipid amphotericin B formulation and a triazole, surgery was performed in 67%. All neutropenic patients received granulocyte transfusions and/or granulocyte colony-stimulating factor. Mucormycosis-related mortality was 20%. In the literature review, mucormycosis-related mortality was 36% for all patients and 66% for patients with disseminated disease. Survival rates were similar over the past 2 decades. The most common underlying disorder was acute lymphoblastic leukemia. Liposomal amphotericin B was the mainstay of treatment. Seventy percent of patients underwent surgery. CONCLUSIONS: Although survival of mucormycosis improved significantly overtime, it plateaued in the past decades. This series shows that with screening, early diagnostics and early antifungal and if possible surgical treatment, mortality is low and even disseminated disease is salvageable if approached aggressively with a combination of surgery and antifungal treatment. Further research focused on diagnostics, combination antifungal and adjunctive therapy is necessary to enhance the survival of mucormycosis in children.

Clinical outcomes of second relapsed and refractory first relapsed paediatric AML: A retrospective study within the NOPHO-DB SHIP consortium.

As treatments for second relapsed and refractory first relapsed paediatric AML transition from purely palliative to more commonly curative in nature, comparative data is necessary for evaluating the effectiveness of emerging treatment options. Furthermore, little is known about predictors of prognosis following third-line therapy. From 2004 until 2019, 277 of the 869 patients enrolled in NOPHO-DB SHIP consortium trials experienced a first relapse and, of these patients, 98 experienced refractory first relapse and 59 a second relapse. Data on patient and disease characteristics within this cohort of 157 patients was analysed to determine probability of overall survival (pOS) and to identify factors influencing survival. Data on early treatment response and complete remission were not available. One and 5-year pOS were 22 ± 3% and 14 ± 3%, respectively. There was no statistically significant difference in survival between refractory first relapsed and second relapsed AML. Factors influencing prognosis included: late relapse, type of third-line treatment, FLT3 mutational status, and original treatment protocol. These data provide a baseline for evaluating the effectiveness of emerging therapies for the treatment of children with refractory first relapsed and second relapsed paediatric AML and evidence that select patients receiving third-line therapy can be cured.

Increased survival disparities among children and adolescents & young adults with acute myeloid leukemia: A Dutch population-based study.

For many cancers, adolescents and young adults (AYAs) have a poorer prognosis than pediatric patients. Our study evaluates survival outcomes of children (0-17 years) and AYAs (18-39 years) diagnosed with acute myeloid leukemia (AML) in the Netherlands between 1990 and 2015 (N = 2058) utilizing the population-based Netherlands Cancer Registry, which includes information on therapy and site of primary treatment. Five- and 10-year relative (disease-specific) survival were estimated for all patients, children and AYAs. Multivariable analyses were performed using generalized linear models (excess mortality) and logistic regression (early mortality). AYAs with AML had a substantially lower 5- and 10-year relative survival than children (5-year: 43% vs 58%; 10-year: 37% vs 51%). The gap in 5-year relative survival was largest (nearly 20 percent-points) in 2010 to 2015, despite survival improvements over time across all ages. The multivariable-adjusted excess risk of dying was 60% higher in AYAs (95% CI: 37%-86%). Early mortality (death within 30 days of diagnosis) declined over time, and did not differ between children and AYAs. In conclusion, AYAs diagnosed with AML in the Netherlands had a worse prognosis than pediatric patients. The survival gap seemed most pronounced in recent years, suggesting that improvements in care resulting in better outcome for children have not led to equal benefits for AYAs.

High-frequency type I/II mutational shifts between diagnosis and relapse are associated with outcome in pediatric AML: implications for personalized medicine.

Although virtually all pediatric patients with acute myeloid leukemia (AML) achieve a complete remission after initial induction therapy, 30%-40% of patients will encounter a relapse and have a dismal prognosis. To prevent relapses, personalized treatment strategies are currently being developed, which target specific molecular aberrations. To determine relevance of established AML type I/II mutations that may serve as therapeutic targets, we assessed frequencies of these mutations and their persistence during disease progression in a large group (n = 69) of paired diagnosis and relapse pediatric AML specimens. In 26 of 42 patients (61%) harboring mutations at either stage of the disease, mutation status changed between diagnosis and relapse, particularly in FLT3, WT1, and RAS genes. Presence or gain of type I/II mutations at relapse was associated with a shorter time to relapse (TTR), whereas absence or loss correlated with longer TTR. Moreover, an adverse outcome was found for patients with activating mutations at relapse, which was statistically significant for FLT3/ITD and WT1 mutations. These findings suggest that mutational shifts affect disease progression. We hence propose that risk stratification, malignant cell detection, and selection of personalized treatment should be based on status of type I/II mutations both at initial diagnosis and during follow-up.

FLT3 and KIT mutated pediatric acute myeloid leukemia (AML) samples are sensitive in vitro to the tyrosine kinase inhibitor SU11657.

New treatment strategies to improve the outcome of pediatric acute myeloid leukemia (AML) are required as 40% of children diagnosed with AML do not survive. Around 30% of pediatric AML patients harbour a mutation in the tyrosine kinases FLT3 (+/-20%) or KIT (+/-10%). In this study we investigated whether pediatric AML samples (N=61) were sensitive to the tyrosine kinase inhibitor SU11657 (similar to the clinically available drug sunitinib) in vitro, and whether sensitivity was related to expression of, and mutations in, FLT3 and KIT. Overall, SU11657 showed only moderate cytotoxicity. A FLT3 mutation was detected in 35% and a KIT mutation in 8% of the samples. FLT3 and KIT mutated samples were significantly more sensitive to SU11657 than WT KIT and FLT3 samples. Samples without KIT or FLT3 mutations, but with a high wild-type (WT) KIT expression were significantly more sensitive to SU11657 than samples with low KIT expression. Further clinical evaluation of SU11657 and sunitinib combined with chemotherapy would be of interest. Inclusion in clinical trials should not be restricted to patients with FLT3 or KIT mutations.

Endogenous vascular endothelial growth factor-C expression is associated with decreased drug responsiveness in childhood acute myeloid leukemia.

PURPOSE: We hypothesized that downstream effects of endogenous vascular endothelial growth factor (VEGF)/VEGF receptor signaling on acute myelogenous leukemia (AML) cell survival resulted in increased in vitro cellular drug resistance and a longer time to kill most leukemic cells in vivo upon drug exposure. EXPERIMENTAL DESIGN: In primary AML cells from pediatric patients, VEGFA and VEGFC mRNA expression and in vitro cellular resistance to nine cytotoxic drugs were studied. As in vivo equivalents for in vitro drug resistance, in vivo AML blast reduction upon drug exposure, measured as blast cell reduction on day 15 in the bone marrow and as time in days from diagnosis to complete remission (CR) were used. RESULTS: Increased endogenous VEGFC levels significantly correlated with increased in vitro resistance for six typical AML drugs in primary AML cells from pediatric patients. Patients with >5% blasts on day 15 showed a 12.9-fold increase in the median VEGFC level compared with patients with < or =5% blasts (P = 0.002). Time to reach CR was studied using linear regression analysis with VEGFC, age at diagnosis, sex, treatment protocol, FAB type, cytogenetic risk profile, and WBC counts as variables. There was a significant positive independent association between VEGFC levels and time to CR (b = 6.02, SE = 1.58, P < or = 0.0001, n = 72). CONCLUSIONS: These results suggest for the first time that higher endogenous VEGFC levels of AML cells are related to decreased in vitro and in vivo drug responsiveness.

A comparison of the in vitro cytotoxicity of daunorubicin and liposomal daunorubicin in pediatric acute leukemia.

Anthracyclines are effective in the treatment of leukemia, but their use is limited because of cardiotoxicity. Liposomal daunorubicin (L-DNR) is potentially less cardiotoxic than daunorubicin (DNR). We compared in vitro cytotoxicity in pediatric acute leukemia samples and found no significant differences between cytotoxicity of DNR and L-DNR.